The MS Thor Liberty left port in Emden, northern Germany, on 13 December and docked two days later in Kotka, southern Finland, to pick up a cargo of anchor chains, said Finnish Customs spokesman Petri Lounatmaa ….

Routine checks by Finland’s traffic safety authority revealed a load of up to 160 tonnes of improperly packed nitroguanidine, a low-sensitivity explosive with a high detonation speed ….

Interior Minister Rasanen said she had not heard of a similar case.

“Of course, there are legal transports of weapons or defence material [through Finland] but in this case the cargo was marked as containing fireworks,” she told Finnish media. “That is quite unusual.”